Remove CIP-42 support

[shazarre]

This PR removes deprecated CIP-42 transaction type support for Celo in favour of CIP-64.

It still keeps functionality to parse and format existing CIP-42 transactions that can be retrieved directly from the blockchain.

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PR-Codex overview

This PR removes support for CIP-42 and treats all transactions with a feeCurrency field as CIP-64.

Detailed summary

• Removed CIP-42 support
• Transactions with feeCurrency are treated as CIP-64
• Updated transaction types and formatters

The following files were skipped due to too many changes: src/celo/types.ts, src/celo/parsers.test.ts, src/celo/getTransaction.test.ts, src/celo/formatters.test.ts, src/celo/serializers.test.ts

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